sock - Tunneled TCP/UDP Sockets

A channel of "type":"sock" is a request to create a minimal tunneled TCP or UDP socket, carrying arbitrary binary data. It may be reliable for TCP, or unreliable to carry UDP. It is designed to mirror the popular socket interfaces for the most common usage patterns, but not as an exhaustive or complete replacement.

The open packet must contain a "sock":value where the value is one of connect, bind, or accept, and usually has a "src":{"ip":"1.2.3.4","port":5678} and/or dst specified. An open may also contain the initial binary BODY payload to deliver if successful.

connect

Request to create a new socket to the given dst. Any non-error packet response indicates the connection was opened. It may have an optional "src":{...} indicating the known original source ip/port when proxying/tunneling.

bind

Request for the recipient to create a listening socket and bind to it. If the src is included, only the port should be specified in it (and defaults to 0 if not) to indicate that the recipient chooses any open port to listen on. The response must include a dst that specifies the current ip and port bound to this channel that the recipient may use/distribute. The recipient should do whatever is necessary to ensure they are public usable addresses.

For an unreliable bind, sending and receiving UDP messages happens on the same channel using a src and dst address. The sender specifies a dst to originate a new UDP message from the port, and receives incoming messages with a src indiciating where they came from.

For a reliable bind, incoming connections will individually open new accept channels from the recipient for each one.

accept

When the recipient has an active reliable bind, any new incoming connection will generate an accept channel and must have the dst of the originating bind along with the src address information.

An accept can also be generated for when a binding is created independently, if a hashname is listening on a TCP or UDP port on behalf of another without using a bind channel. The semantics of dst and src are the same, and the accept channel may be reliable or unreliable.